Giant new test stands will rise at Marshall Space Flight Center as Space Launch System grows

"We won't shake it, but we will bend it and twist it and compress it and pull it."

View full sizeThis test stand will be used to test the smaller of two fuel tanks on the core stage of NASA's Space Launch System in Huntsville. It will also be used to test the adapter that will join the core to the upper stage. (NASA)

NASA engineers are building on the historic foundation of rocket testing in Huntsville - literally - as they prepare for critical stress tests on the core of Space Launch System, America's next deep-space rocket.

Two large new test stands are being designed for Marshall Space Flight Center, and one of those stands will be built atop the bedrock-deep foundation of the stand Wernher von Braun used to test the massive F-1 Saturn V engines.

These new tests won't shake the ground across Huntsville as those Saturn V engine tests did, because NASA does its engine testing now in the vast open space of the Stennis Space Center in south Mississippi.

But the tests in Huntsville will be critical to the new rocket meeting its tight flight schedule, and the testing program itself is a complicated choreography. For example, giant barges will transport the rocket's core components - including a 185-foot tall liquid hydrogen tank - up Alabama's river system to Huntsville from the Michoud Assembly Facility near New Orleans where they will be made.

The core stage of the Space Launch System is 200 feet tall. By comparison, a Saturn V first stage was roughly 75 feet tall. The core is composed of five parts: two fuel tanks, a main engine compartment with associated plumbing for fueling, an intertank ring to join the two tanks and a top ring to attach the core to the Orion upper stage.

Breaking the core into the five pieces "allows us to structurally test them," SLS Stages Elements Manager Tony Lavoie said Tuesday. "We do a lot of things by analysis, but the analysis has to be anchored with real testing."

The two new tanks are the reason for the new test stands. But NASA has to test each of the five parts to be sure it can handle the stresses and loads of liftoff and ascent into space. "We have to throw the worst-case environment we believe they will see in flight against them on the ground," said Sherry Huddleston, construction of facilities and structural test article manager.

Prime core stage contractor Boeing studied the tests needed, and Marshall "made the most sense" as the location, Huddleston said. It has the most existing facilities, the in-house expertise and the proximity to Boeing in Huntsville.

"It's the two tanks that are driving the new test stands," Huddleston said, "and that's primarily driven by the sheer size and the extreme loads that have to be put on the test articles."

The liquid hydrogen tank is the reason for the big new, 215-feet-high test stand that will rise on the foundation of stand 4693 used for the Saturn V engine hot-fires. Engineers will hang the 185-foot-tall tank vertically, load it with enough liquid nitrogen to cover critical areas and apply stress. "We won't shake it," Huddleston said, "but we will bend it and twist it and compress it and pull it."

The second, smaller tank will be used to test the liquid oxygen tank and the forward skirt that will join the core to the Orion upper stage.

The tanks will be be built at Michoud while the test stands are built at Marshall. All of that will occur in 2014. Testing will begin in late 2014 or 2015 and continue into March or April of 2016.

That gives NASA only about a year to fix the design if testing reveals any major issues. The space agency has until 2017 to build a flight-worthy core set. That's the year Congress has mandated that SLS fly with an unscrewed Orion capsule on top.

If a major problem develops in testing, NASA probably wouldn't have time to build an entirely new core and test it before the 2017 deadline. But there would be time to tweak the existing design with, for example, a brace of some sort, and retest in Huntsville. There would also be time to test a revision in the "green run" test firing of the full core at Stennis in late 2016 or early 2017. A crew will not sit on top of the stack until 2021.